Iain Pears' An Instance of the Fingerpost is a skillful work of historical fiction. An intricate and well-constructed book, it is heavy with complexity and the need to re-evaluate that which has been said before. It consists of four accounts of actions centred around the same period, and around the same singular individual. The author is at his most skillful when constructing the characters of the four narrators and, from a combination of their thinking processes and experiences, constructs a viable narrative for each, none of which are entirely adequate for understanding what transpires.
The central theme of the book is probably the nature of truth. All the science and experimentation of the first part strikes at it, as does the fruitless quest of the second, the subterfuge of the third, and the historical analysis of the fourth. None are entirely satisfying - despite the revelatory tone of the final account. It obviously could not be so illuminating without the contributions of the others. Indeed, the overall thrust of the book is to make one doubtful of whether truth can ever be known. For me, that was highlighted by how my willingness to believe the conclusions of any character had much to do with how personally appealing I found them.
When it comes to the science and medicine, one can maintain the hope that truth is being progressively more closely approximated in our theories and models. Certainly, doctors today are dramatically more likely to help you than they were at the time during which this book is set. We also have a far better understanding of many of the physical and chemical phenomena described in the book. Insofar as the natural world is concerned, truth is not such a problematic thing. We can say, with a very solid authority, that penguins mate for life. Much of that conviction evaporates, however, once people get involved in our consideration. Motives, thoughts, and personalities are all ephemeral things, difficult to comprehend both from within and without. We don't get the matter of the thing itself, but rather a story constructed about that matter that will need to suffice. The same is probably true for science, but we are able to make better stories. That is probably primarily because the natural world is in important senses unchanging: in terms of the phenomena that underlie and direct it.
The book's remarkable conclusion takes everything back to the question of judgment and truth. While I wouldn't be so heartless as to lay out the surprises, the book definitely ends on a very strong note. I recommend the book, particularly, to anyone with an interest in British history around the time of the Civil War and Restoration.